The Aging Transgenic Rodent/Pathology Core (ATRPC) is directed by Evan Keller. The major purpose of the ATRPC is to provide Nathan Shock Center (NSC) and University of Michigan (UM) scientists with aged mice of the genotypes that provide otherwise unavailable opportunities to investigate the basic biology of aging or the pathophysiology of age-related disease states. A facility such as the ATRPC operated by the NSC at the UM does not exist anywhere else in the country. The ATRPC' s MTRC is primarily dedicated to exploiting the wide range of mutant and transgenics currently available, but not yet studied in the context of aging, for gerontological research . The ATRPC functions as a service core with the following specific aims: 1) the support of the per diem costs of aging a wide variety of mutant/transgenic rodents, (2) facilitating gross necropsy and histopathology of age-related lesions for genetically ~ modified mice, and (3) creating a database of the genetically -modified mice that are available for NSC and UM investigators. Over the previous five years of support, the ATRPC as supported thirteen projects with 12 faculty sponsors. Most projects were funded for 2 years, which was the usual time required to obtain mice at the ages required for the study. The projects funded during the current granting period included: evaluating aging effects on methylation in a methyltransferase knockout mice, determining aging effects on a humanized androgen receptor in mice, evaluation of wnt with age in bone and evaluation of estrogen receptor mutations with age. Several of these projects have led to publications and grant applications. The ATRPC has had a significant impact on the use of genetically-modified mice for NSC scientists on the UM campus and among their colleagues at UM and elsewhere.